Just as a point of clarification to Etoh's post ... there is no such thing as a "side ao".
"AO" stands for "Adjustable Objective"
When you have a scope that has a parallax adjustment, you either have a scope with an "Adjustable Objective Lens", or you have a scope with a "side focus parallax knob".
If you had a "Side Adjustable Objective" scope, you'd have a rather unique item, seeing as how you'd have an adjustable objective on the side of your scope.
